The general procedure for the synthesis of quinoline-8-sulfonyl chloride from quinoline-8-sulfonic acid is as follows: chlorosulfonic acid (6.0 g, 51.5 mmol) was added to a reaction vessel fitted with a magnetic stirrer under nitrogen protection. Quinoline (1.0 g, 7.74 mmol) was slowly added under cooling in an ice bath. Subsequently, the reaction system was gradually warmed to 140 °C and the reaction was continuously stirred at this temperature for 10 hours. Upon completion of the reaction, the system was cooled to 40 °C and thionyl chloride (2.0 g, 16.0 mmol) was added dropwise. Then, the reaction temperature was raised to 70 °C and the reaction continued to be stirred for 4 hours. At the end of the reaction, the reaction system was allowed to cool naturally to room temperature, and the reaction solution was slowly poured into ice water, which immediately precipitated a solid. After stirring the mixture for 30 min, the solid product was collected by filtration and dried under vacuum to give quinoline-8-sulfonyl chloride (1.7 g, 99% yield). Mass spectrometry analysis showed m/z: 228.0 (M+1).
